[matoous]

A small edit can rerun an injection query across a large syntax tree even when the source cannot contain a match. In the editor's JSON workload, looking for comment injections dominates otherwise incremental whitespace edits.

Add an optional injection.source-pattern property. It is a necessary condition supplied by the query author: if every injection pattern has a guard and none of those regexes matches the source, skip the injection query traversal. The regex reads the rope directly. Patterns without a guard retain the existing behavior, and existing injections are still mapped and pruned when the last marker is removed.

For example, JSON's comment injection can use (#set! injection.source-pattern "/[/*]"). Text without either comment opener cannot contain a comment injection. A marker inside a string is a safe false positive and falls back to the normal query. An incorrect guard can suppress real injections, so the README documents that contract; no existing query behavior changes unless it opts in.

Comment-free JSON array	Without source guard	With source guard
1,000 rows: insert and inverse	1.59 ms	0.556 ms
10,000 rows: insert and inverse	17.04 ms	3.39 ms
100,000 rows: insert and inverse	195.53 ms	38.17 ms

Both sides use the same patched dependency binary; only the JSON injection query property changes. The comparison uses the Mitos release-mode JSON probe: insert one space in the middle of a comment-free array and apply its inverse, taking the median of 11 pairs. It measures the full synchronous syntax update pair, not typing-to-screen latency. The editor change is mitos-editor/mitos#574 and adds the JSON query property. Its ignored json_update_performance test contains the probe. Documents containing a possible marker still execute the existing injection query.

Validation: all 45 upstream tests passed, formatting passed, and focused Clippy passed with warnings denied. Tests cover comment insertion/removal, a mixed guarded/unguarded query, invalid regexes, a marker crossing rope chunks, and a marker inside a string.

cargo test --locked -p tree-house
cargo fmt --all --check
cargo clippy --locked --no-deps -p tree-house --all-targets -- -D warnings

[matoous]

Moved this proposal to our fork: mitos-editor#1.